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Discussion Starter #1
I have a 2012 e70 50i ..... recently my comfort access just stopped working for no apparent reason. At first i thought maybe i needed to change my key fob battery, I've done that and still comfort access is not working. Is this a common problem other e70 owners are facing and if so can some one please give me some insight on how to remedy this.
 

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Nuclear engineer
02/2012 X5 35d M57Y CPO 98K miles NOKIAN WR G3 12K miles
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Not for me.

Which aspect precisely of ***8216;Comfort Access***8217;?

www.NewTIS.info
 

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Discussion Starter #3
when i purchased the vehicle one of the rear door handles didn't work with comfort access. however i was fine with that because the other three worked, and i mainly use driver door anyway. now all the doors are not working with comfort access, the car is still able to start without key in slot. From what I've been reading online, if one door handle goes bad it can cause them all to stop working :dunno:
 

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What was that?
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when i purchased the vehicle one of the rear door handles didn't work with comfort access. however i was fine with that because the other three worked, and i mainly use driver door anyway. now all the doors are not working with comfort access, the car is still able to start without key in slot. From what I've been reading online, if one door handle goes bad it can cause them all to stop working :dunno:

Are handles hot by any chance?


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both keys have the same behavior?

Do you have the ability to read codes/check modules for errors?

Any evidence of water intrusion? under the rear trunk, under the carpeting in the front footwell areas?
 

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Discussion Starter #6
@Ard.... i haven't felt any heat coming off the handles, but I'm going to check this morning. Its my goal to properly diag this problem and fix myself.



@Argento.... i bought vehicle with only one key so unfortunately I'm unable to compare my key to another.
I do have a snap-0n scan tool that ill be plugging in today, hopefully it can give me an idea of what's going on. The push start still works without key in slot which if im correct is part of comfort access(i could be wrong), so i don't believe the fuses have any water damage but ill check today

after watching a video last night pertaining to this issue, im under the suspicion that because one door handle was defective, the module shut down the system in order to prevent battery drainage. im conflicted in this prediction now due to an article i read this morning stating that each handle should work independently. Hopefully after plugging scan tool in ill have a better assessment of this issue.
 

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Nuclear engineer
02/2012 X5 35d M57Y CPO 98K miles NOKIAN WR G3 12K miles
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I had a comfort access sensor fail which caused the trunk area not to open when standing there and pressing the trunk button with CA key in pocket. The sensor is located under the bumper cover and was very simple to change. I know there is at least one separate sensor for the doors so maybe that one failed? Does opening the trunk work with CA? If so it would point to the system working so maybe just need a new sensor. I recall someone posted a picture of one in the cargo area (near the spare tire well) asking what it was and I replied it's a CA sensor because i had just replaced the one under the bumper. I also had a code set but don't recall exactly what it was. Also, it took a while for the sensor to completely fail. It started by sometimes not working to open the trunk to finally not working at all. Hopefully your issue is an easy fix like mine was.
 

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Discussion Starter #9
two codes were generated when i plugged in scan tool. 2F4A interface EWS(immobilizer engine ECU). and A103 CAS electric immobilizer, immobilizer bus fault.
 

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so at the moment im a little stumped, im now receiving an intermittent no signal from key when trying to use push start. However it eventually works...... im thinking the cas module may need changing now and its not door handles, but with my luck i probably have a faulty handle and need to replace cas.:cry:

looking for any suggestions to remedy this problem. so far my plan is to start removing door handles one at a time to see what happens, then possibly move on to cas next if this doesn't help solve it.
 

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Nuclear engineer
02/2012 X5 35d M57Y CPO 98K miles NOKIAN WR G3 12K miles
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I'll bet that there is a BMW Test Plan© for your problem.

A Diagnostic Trouble Code does not identify a failed part for changing, but identifies a symptom of a problem that can be caused by any number of failed components or adjustments to be differentiated among by execution of a BMW Test Plan© guide through the fault tree.
 

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sooooo..... the immobilizer bus fault in the CAS basically means theirs an error in the CAS network. the ecu reading is basically the cars computer acknowledging theirs an error in the CAS....
The CAS is technically its own bus network, in such a network you need three things in accordance for proper functionality: GROUND,POWER, and SERIAL DATA CONNECTION in all modules. Meaning if any part of your CAS fails it will cause disruption in the whole network. If one door handle fails eventually after so many error codes your CAS may actually just stop working, until the bus network is complete again.


In conclusion i disconnected door handles one by one and tested CAS after each. My culprit turned out to be my rear passenger door handle. From what I've seen through this, i can leave door handle disconnected and my CAS works just fine. But i will be ordering another and just replacing it.


i hope my X5 CAS journey and conclusion can help someone else out in the future.
 

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when i purchased the vehicle one of the rear door handles didn't work with comfort access. however i was fine with that because the other three worked, and i mainly use driver door anyway. now all the doors are not working with comfort access, the car is still able to start without key in slot. From what I've been reading online, if one door handle goes bad it can cause them all to stop working :dunno:
I don't think it will cause all system to shot down. My X5 had an issue with all doors stop opening after I changed a battery in a key fob. I installed a new battery inserted the fob in a slot in a panel DONE. after 5 minutes all was working great again.
 

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sooooo..... the immobilizer bus fault in the CAS basically means theirs an error in the CAS network. the ecu reading is basically the cars computer acknowledging theirs an error in the CAS....
The CAS is technically its own bus network, in such a network you need three things in accordance for proper functionality: GROUND,POWER, and SERIAL DATA CONNECTION in all modules. Meaning if any part of your CAS fails it will cause disruption in the whole network. If one door handle fails eventually after so many error codes your CAS may actually just stop working, until the bus network is complete again.


In conclusion i disconnected door handles one by one and tested CAS after each. My culprit turned out to be my rear passenger door handle. From what I've seen through this, i can leave door handle disconnected and my CAS works just fine. But i will be ordering another and just replacing it.


i hope my X5 CAS journey and conclusion can help someone else out in the future.
Very good to know. Did the cas reset automatically (each time you would disconnect a differnt handle)? Or did you need to reset/restart the module?
 
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